Control mechanism



June 13, 1950 E. P. BULLARDJII 2,511,821

coumor. MECHANISM Original Filed June 24, 1944 2 Sheets-Sheet 1 lNvENTuRDY EDWARD P. B uLLARL lU E. P. BULLARD,

NTROL MECHANISM 2 Sheets-Sheet 2 Original Filed June 24, 1944 L...J'INVEN TDR E'nwnnn RBuLLAnnJZI Patented June 13, 1950 2511,1221 comaor.MECHANISM Edward P. Ballard, III, Fail-field, Conn, assignor to TheBullard'company, a corporation of Connecticut Original application June24, 1944, Serial No.

1945, Serial No. 586,799

This invention relates to controls for apparatus capable of producing arelatively large number of functions. Particularly, it relates to acontrol mechanism that will automatically select, in any order within acycle of operation any one or more functions of which an apparatus iscapable, while providing separate means for very accurately determiningthe extent of each of said functions. This is a division of applicationSerial Number 541,986, filed June 24, 1944, in the name of Edward P.Bullard, III.

Ordinarily, the accuracy that can be obtained in the operation ofmachine tools, and particularly in the automatic-cycle operation ofmachine tools is limited by the accuracy that can be obtained withcertain essential elements of the automatic control. For example, whenelectrical circuits are employed to control the movement of a member,the accuracy that can be obtained is limited by the accuracy of theoperating parts of the electrical circuit, and particularly by theaccuracy of those parts which are utilized repeatedly to efl'ectstopping of the movement of the member such as trip switches. Machinetool operation requires an accuracy, in stopping the movement of a tool,in the nature of .0005 of an inch. Not only must such accuracy beproduced, but it must consistently be maintained regardless of the rateat which the tool is being fed. Prior known electrical equipmentincluding contact-making circuits for controlling the movement of a toolfails to produce accuracies of the order required in machine toolcontrol as set forth above. This is primarily true because detrimentalarcing between critical contacts of such equipment produces a moltencondition on the contact surfaces, thereby changing the point at whichsuch contacts subsequently make the circuit. In order to overcome thiscondition, by

reducing to a minimum the duration of arcing, prior known switchesemploy a quick, wide separation of the contacts when it is desired todeenergize such a control circuit. A wiping action between contactswhile separating them is also employed to smooth the rough contactsurface caused by the molten condition due to detrimental arcing. Theseprior known switches often employ metal-flexing members that areoperated in response to tool movement for producing the quick, wideseparation of contacts. The accuracy of such constructions is limitedbecause the metal-flexing members fail to respond at exactly the samepoint of tool movement upon repeated operations under the sameconditions.

13 Claims. (Cl. 171-97) Objects of the present invention include the I.

Divided and this application April 5.

provision of a control mechanism for cycle-operating apparatus of thetype that involves means adapted repeatedly to be moved along one ormore paths in any order and for any distance; the provision of a controlmechanism for a machine including means capable of performing amultiplicity of functions, wherein the control is adapted to render saidmeans fully automatic, but still preserve its manual operativeness; andthe provision of a control mechanism for a machine of the type thatinvolves means adapted repeatedly to be moved along one or more pathsfor different overlapping distances within a cycle of operation.

Other objects of the invention include the provision of an electricalcontrol circuit that can be energized repeatedly by the engagementbetween movable contact elements at exactly the same point relatively toeach contact element; the provision of such an electrical controlcircuit wherein the surfaces of the energizing contact elements are notaltered by continued repetitive use, by detrimental arcing or wear dueto a sliding action; the provision of such an electrical control circuitin which the energizing contact elements can be brought into engagementas slowly as desired to energize the circuit without detrimental arcing;the provision oi such an electrical control circuit that istie-energized before the contact elements are separated that areemployed for energizing it; the provision of an electrical controlcircuit including a plurality oi. circuitenergizing contacts, eachincluding movable contact elements, that are successively connected intothe circuit and each of which embodies the above-noted characteristics;the provision of such an electrical circuit that is energized by theengagement between one set of contact elements and deenergized by theseparation of another set of contact elements, and in which the contactelements of the first set are separated after the separation of theelements of the second set and the provision of an electrical controlcircuit for a multi-function apparatus wherein the duration of eachfunction is determined by the engagement of separate circuit-energizingcontact means that are successively connected into the circuit and inwhich said circuit embodies all of the above-noted characteristics.

Other objects include the provision of apparatus capable of a relativelylarge number of functions which embodies means for selectlnfl in anyorder, a relatively great number of any of said functions within a cycleof operation and including separate electrical switch means for eachfunction within said cycle of operation; the provision of such anapparatus in which each switch is arranged in cooperative positionrelatively to a separate switch-actuating dog, and in which cooperationbetween the two is responsive to a function of the apparatus; theprovision of such an apparatus wherein the relatively great number ofswitches and dogs is so constructed that a maximum number is included ina minimum of space; the provision of such an apparatus wherein theswitches are actuated by relative movement between them and their dogsin response to the functions of the apparatus; the provision of such anapparatus in which each switch includes single contact means havingmovable contact elements operable to energize a circuit by the action ofa dual-directional-motion actuator; the provision of such an apparatuswherein each switch is so constructed that cooperative abuttingengagement between it and its dog occurs completely within a surface ofthe dog at right angles to the direction oi relative movement betweenthe switch and its dog: and the provision of such an apparatus in whicheach switch employs means for multiplying the relative motion between itand its dog and transmits such amplified motion to the single-contactmeans through rigid compression members.

Another specific object of the invention is the provision of a controlfor a machine tool of the pre-settable cycle-operating type involvingcontrol means that is moved from position to position for selectingsuccessive functions within a cycle of operation, and wherein thefunctions are terminated independently of the movement of the controlmeans.

The above, as well as other objects and novel features of the invention,will become apparent from the following specification and accompanyingdrawings, in which:

Figure 1 is a schematic layout of the essential features of theinvention;

Figure 2 is an enlarged detail sectional view taken substantially alongline 2-2 of Figure 1:

Figure 3 is a plan view taken along line 33 of Figure 2;

Figure 4 is an elevational view taken along line l-l of Figure 2; and

Figure 5 is a detail ofthe apparatus shown in Figure 2.

Referring to Figure 1, a feedworks transmission Tn includes a shaft 31that is driven by a headstock transmission not shown. The shaft 31supports two bevel gears 38, 39 for free rotation. A clutch I is locatedbetween the gears 38 and 38 and it is splined to the shaft 31. Bothgears 38 and 39 mesh with a bevel gear Al. The gear ll is fixed to ashaft 42'. Spur gears 43 and II are fixed to the shaft 42' and they meshwith corresponding gears l and 46 Journaled on a shaft 41. The shaft 41is hollow and a diving key 48 extends thereinto. The key 48 is adaptedto be moved from engagement with gear 45 to engagement with gear 46selectively for a purpose to be described later. Spur gears 49, 5 5i and52 are fixed to the tubular shaft l'l. Spur gears 53. 54, 55 and 56 arejo'urnaled on another shaft 42. The portion of shaft II on which gears83 to 56 are journaled is of tubular construction for receiving a divingkey 51. A bevel gear SI is fixed to the end of shaft 42 and it mesheswith a bevel gear 60 fixed to a worm 38. From the foregoing it isevident that worm 36 ma be rotated in either direction at any one 4 ofeight different speeds depending upon the positions of diving keys IIand I1 and clutch. B.

A screw 30 threads into a boss on the back of a saddle 28. A splinedshaft ll supports a worm ii for sliding movement therealong. The worm 6imeshes with a worm wheel 62 on the back of saddle 28. The worm I2 isfixed to a shaft 88 that also supports a spur gear 84 in mesh with arack BI on the back of a slide 29. The shaft 63 is iournaled in bearingson saddle 28. Rotation of screw Iii. therefore, moves saddle 2t andslide 29 horizontally and rotation of splined shaft ll moves slide 29along the bearings formed therefor in saddle 28. Accordinsly. movingworm 38 into engagement with gears 32 and 31 will cause the movement ofhead Ht along its respective paths in either direction at any one ofeight different speeds depending upon the position of clutch 40, key Itand key 51.

A housing 68 is attached to the end of a cross rail C opposite thatwhich supports the feed works Th. This housing is adapted to supportcontinuously-driven oppositely-rotatable means that is adapted to beconnected to and disen-' gaged from the screw 30 and the splined shaft31 by the selective operation of rods 61 and Bl. These rods are axiallymovable by the oscillation of crank arms 89 and III. This constructionprovides means for moving the turret head Ht along either of its pathsat relatively fast traverse speeds.

Crank arms 89 and III are adapted manually to be o erated by hand leversII and 12. These crank members are also adapted to be hydraulicallyactuated by pistons within cylinders 13 and I4. The pistons within thesecylinders are connected to the crank members 69 and ill by theconnecting rods 75 and 16, respectively. The worm 36 is adapted manuallyto be moved into and out of engagement with gears 32 and 33 by a handlever (not shown) which latter is operated by a piston in a, cylinder19. The reversing clutch 40 is adapted manually to be moved by a handlever 80 fixed to the clutch 40. Clutch Iii is adapted hydraulically tobe actuated by a piston Within a cylinder Bl which is connected to theclutch MI by a link 82. The diving key 51 is adapted manually to bemoved by a hand lever 83, while the diving key 48 is manually operableby a hand lever 84.

The p ston and cylinder constructions 13, it, 19 and BI are the sameand, therefore, only one will be described. The cylinder 13 includes adi viding partition that cooperates with an end 86 to support piston 81.The piston 81 includes end portions that extend through the partition 85and the end portion 86. A rod 88 fixed to the piston 81 extends beyondthe partition 85 into another chamber of cylinder 13.oppositely-disposed discs 89 and 80 are mounted on the rod 88 for freemovement relatively to said rod. A nut BI is screwed onto the end of therod 88 in en gagement with the disc 90. The disc 89 abuts against ashoulder 89' between rod 88 and the one end portion of piston 81. Fluidunder pressure is adapted to be selectively admitted to upposite facesof piston 81 through conduits 92 and 83. Constant pressure is adapted tobe supplied through a conduit M to the chamber of cylinder 13 thatcontains the discs 89 and 9G. The effective pressure area of the discs89, so is less than the effective pressure area of the piston 81.Consequently, admission of pressure to the cylinder I3 through the lines92 and 93 will cause the piston 81 to move within the cylinder 18.Removal 01' pressure from both lines 92 and 93 will effect theinstantaneous centralization of the piston 91 within the cylinder 13.This construction provides means for positively moving the cranks 69,I0, clutch 40 and wor 36 to their active positions and causesneutralization of each of these elements upon removal of the pressurefrom the corresponding pistons thereof.

The diving keys 4B and 51 are adapted hydraulically to be actuated bycylinder mechanisms 95 and 95 (see application, Serial No. 541,986 filedJune 24, 1944) Fluid under pressure is adapted selectively to besupplied to the piston mechanism 8| through conduits H9 and H1. Fluidpressure is adapted to be supplied to the piston mechanism 14 throughconduits H8 and H9. Fluid under pressure is adapted to be supplied tothe piston mech anism 19 through conduits I20 and I2I. Fluid underconstant pressure is adapted to be supplied to piston mechanisms 0|, 14and 19 through conduits I22, I23 and I24, respectively. This constantpressure fluid is supplied to the conduits I22, I23 and I24, as well asto the conduit 94 by a pipe I25 that leads from a main source of fluidsupply P through a duct I26 and a valve I21.

Conduits 92, 93, 90. 99, I00, IOI, H4, H5, H9, II1, H9, H9, I20 and I2Iare adapted to be supplied with fluid under pressure from the mainsource P by a pipe I28 that leads from valve I21 and is connected to anelongated valve body I29. The valve body I29 is provided with acentrallydisposed longitudinally extending passage I30 throughout itslength. It is also provided with a plurality of transversely-disposedvalve chambers of identical consctruction within which are located valveplungers I3I to I44, inclusive, for conduits 92, 93, 99, 99, I00, IOI,H4, H6, H1, H9, H9, I20 and I2I. Valve plunger I44 is employed as aspare and is not shown connected to a conduit. Since all the valveplungers I3I to I44 are identical, only plunger I3I will be specificallydescribed. It comprises a valve stem I45 having a valve head I45 at itslower end and an upper head I41 at its upper end. The area of the head Iis substantially less than that for the head I41. Consequently, theconstant supply of fluid under pressure within the valve body I29maintains the plunger I3I in its upper position. With plunger II in itsupper position. the lower head I40 prevents the passage of fluid underpressure through a discharge duct I49 which is connected to the conduitH9. Upon downward movement of the plunger I3I, the head I thereof movesinto a chamber I49 having an exhaust I50, whereupon fluid from line I20may pass said head and empty into duct I43.

The conduits IIB, H9, 92 and 93 control the operation of the arms 10 and69, respectively, for rendering effective the quick traverse movement ofthe head Ht. During a machining operation it is necessary to provide adwell at the end of any feeding operation for the purpose of cleaning upthe work. Accordingly, time delay mechanisms I51, I52, I53 and I54 areprovided between the valve body I29 and the conduits H8, H9, 92 and 93.Reference is made to the parent application for specific details ofconstruction.

The plungers I3I to I44, inclusive, are adapted selectively to bedepressed by the step-by-stcp rotation of a function drum I10 about ahorizonta axis. The drum I10 is provided with a series ofcircumferentially-disp0sed openings I1I forming means whereby dogs I12can be attached to said drum. There is a series of such holes I1I inline with each of the plungers I3I to I44, inclusive,

as well as other such series of openings for purposes to be describedlater. The drum I10 is shown in the form of a cylinder having trunnionsI13 and I14 which are supported in the usual manner in hearings in thehousing of the function control mechanism F. The drum I10 is adapted tobe indexed a predetermined number of degrees about its horizontal axisintermittently so that the dogs located on the drum in alongitudinally-disposed row of openings I" will become effective todepress the selected plungers I3I to I 44, thereby to operate themachine in a manner to be described later. Ratchet wheels I15 and I10are fixed to the trunnion I13 of the drum I10. The ratchet wheel I15 isemployed to index the drum I10, while ratchet wheel I19 serves as aretaining means for locking the drum 10 in each of its indexedpositions.

Pressure fluid from a main source P branches all from the line I26through a valve 2| 0, lines 2I I, 2I2, a manually-operable valve 2l3 tobe described later, and a conduit 2 I4 that is connected to an inlet 200of the housing I10. The valve 2I0 comprises ball members 2I5, 2I5 thatare joined by a slender rod 2I1. The balls 2I5 and 2I6 are adapted toseat in a valve body 2I0 to prevent the iassage of fluid thereby. Theconstruction and .rrangement of parts are such that when ball 2I5 isengaged with its seat, ball 2I0 is out of engagement with its seat, andvice versa. Accordingly, movement of the balls 2I5, 2l8 to the left, asviewed in Figure 1, will permit fluid under pressure to be admittedthrough lines 2, 2I2. manually-operable valve 2 I3, line 2, to inlet 2".Upon release of the force moving balls 2I5 and IIS to the left, asviewed in Figure 1,.they will move to the right under the combinedinfluence of the pressure from the source P acting against the ball 2I5and a spring 204, thereby cutting off the flow of fluid under pressureto the inlet 200. The constant supply of pressure to inlet 209 issupplied from the branch conduit 209.

Intermittent operation of the valve 2I0 will cause the intermittentindexing of the function drum I10 to effect the depression of selectedof the valves I3I to I44 for controlling the operation of the machinetool. In order to reduce to an absolute minimum the time required toexhaust the valve piston mechanisms 0|, I4, 19 and 13, means is providedfor effecting their exhaust independently of the indexing of the func-'tion drum. If the exhausting of these piston mechanisms were effected bythe upward movement of the valve members I3l to I44, instantaneousaction could not be obtained since a definite time interval is requiredin moving the drum from one position to the next. Accordingly, thepresent invention overcomes this difllculty by providing a unique valvemechanism between the piston mechanisms 13, 14, 19 and 0| and the valvebody I29 including the time delay devices I5I, I52, I53 and I54. Thisvalve mechanism is designed to effect instantaneous exhausting of thepiston mechanisms 13, 14, 19 and Ill independently of the action of theindexing mechanism for the function drum I10. It comprises an elongatedbore 220 within which a plurality of indipendent piston members MI isadapted to be reciprocated for a limited distance. Each of the pistonmembers MI is identical and comprises a head portion 222 and a stemportion 223. They are arranged in aligned abutting relation. The bore220 is provided with a plurality of ports 224 to which the conduits H9,H9, 92, 93, H6, H1,

I23 and "I are connected. It is also provided with a plurality of inlets225 to which the chambers ior valves I3I, I32, I33, I34, I35, I33, I31and I33 are connected. The bore 223 is also provided with a plurality ofexhaust ports 223. The construction and arrangement oi! parts are suchthat normally the piston members 22l are in abutting relation, as shownin Figure 1, with their head portions 222 overlapping or covering theexhaust ports 223 and permitting free passage between the valve body I23and the conduits H3, H3, 32, 33, H3, H1, I23 and HI. Constant pressureis supplied to the left-hand end of the bore 223 through a branch 221 ofthe conduit I23, normally maintaining the pistons 22I in the positionshown in Figure 1. A branch line 223 of the line 2 is connected to theright-hand end of bore 223 and acts upon the head 222 of therightward-most piston 22I. Accordingly, upon the intermittent actuationof valve 2 I 3, the piston members 22I will be moved leitwardly suchthat the exhaust ports 225 will be uncovered and the inlet ports 225will be covered. When this occurs, the conduits H3, H3, 32, 33, H3, H1,I23 and HI will be instantly exhausted before indexing of drum I13 willtake place by the action of the fluid under pressure in line 2I4. Thisconstruction greatly increases the accuracy of the feed knock-out, aswell as the traverse knock-out. That is, neutralizing oi the feed andtraverse clutches and drop worm 33 is instantly accomplished regardlessoi the time required to index drum I13.

That which has been described comprises selectively-operable mechanismfor causing the head Ht to produce any function of which it is capablein accordance with the operation of valves I3I to I44. The extent of anyfunction selected by the drum I13 is adapted to be determined bymechanism associated with the movable head Ht. This mechanism isdesigned to provide a separate function determining means for eachfunction called for by a setting of dogs I12 along alongitudinally-disposed row of openings ill on drum I13. It comprises inthe present embodiment, switch-trip supporting means 223 to 233,inclusive, one for each of the longitudinallydisposed rows of holes IIIon the drum I13. Although only eight such supporting means and eightlongitudinally-disposed rows 01 dogs I12 on drum I13 are shown, it is tobe understood that any number of such supporting means and longitudinalrows of dogs I12 may be employed. In practice, it has been found thatabout forty such supporting means and rows of dogs on drum I13 areadequate. The switch-trip supporting means are mounted on a panel 231rigidly attached to the saddle 23 of the machine. Similarly, supportinmeans 233, 233, 243, I, 242, 243, 244 and 245 are mounted on a panel 243fixed to the cross rail C. An arm 241 is fixed to and movable with theslide 23 and includes a rightangularly disposed portion 243 havingswitches 243 above the supporting means 223 to 233, inclusive. An arm253 is fixed to, and movable with the saddle 23 along the cross rail Cand it includes a right-angularly disposed portion 25I having switches252 above each of the supporting means 233 to 245, inclusive. Theconstruction and arrangement of the parts are such that movement ofslide 23 along the bearings in the saddle 23 will cause the switches 243to move along means 223 to 233, inclusive, and horizontal movement ofsaddle 23 will cause the switches 252 to move along the means 233 to245, inclusive.

Adiustably-mounted dogs 233 are adapted to be located along each of thesupporting means 223 to 233 and 233 to 243, inclusive. The switch 243above means 223 is connected to the switch 252 above means 233 by acommon wire 254. Switches 243 and 252 above means 233 and 233 areconnected by a common wire 255. Switches 243 and 252 above means 23I and243 are joined by wire 253. Wire 251 joins switches 243 and 252 abovemeans 232 and 24I. Wire 253 joins switches 243 and 252 above means 233and 242. Switches 243 and 252 above means 234 and 243 are Joined by wire253. Wire 233 joins switches 243 and 252 above means 235 and 244.Switches 243 and 252 above means 233 and 245 are joined by wire 23I. Thespecific construction of the switches 243, 252 and the switch-trippingdogs 253 will be described later.

Each wire 254 to 23I, inclusive, is connected to a separate contact 233of a, distributor 234 that is mounted about trunnion I14 01' functiondrum I13. The-contacts 233 are located about the periphery of anon-rotatable cylindrical member 235 of the distributor 234 such thatwires 254 to 26I are successively adapted to be contacted by a brush arm233 ilxed to and rotatable with the drum I13. A binding post 231 isprovided with the group of contacts 233 as the "nofunction position 01'the drum. The binding post 231 is provided with a line 233 having amanually operated push-button 233 between the binding post 231 and aground connection for the purpose of initiating a cycle of operation aswill be described later. The brush arm 233 includes a contact member 213that is maintained in rubbing engagement with a fixed contact 21i towhich another binding post is fixed and mounted in the non-rotatablecylindrical member 235 of distributor 234. The contact 2" is providedwith a conductor 212 that extends through a switch 214, thence to acompound switch mechanism 215 adjacent the drum-indexing mechanism. Theswitch 215 includes a normally closed contact 213 and a normally opencontact 211. The conductor 212 is connected to one pole each of theswitches 213 and 211. The opposite pole of the switch 211 is groundedand the opposite pole of the switch 215 is connected by a conductor 213that extends to and is connected with a source of electrical energy G.The source of energy G also is in series connection with a solenoid 213,the opposite side of which is grounded. The solenoid 213 is adapted uponenergization to cause the pivoting 0! an arm 233 about a pivot 23I tooperate the valve 2I3.

Operation of the switches 243 and 252 grounds the wire 254 to 23I thatis connected to it, to create a circuit through the solenoid 213. Assume that brush 233 is in contact with the binding post 253 for theconductor 253 that is common to the switches 243 and 252 for theswitchtrip supporting means 234 and 243, respectively. Further, assumethat the head Ht is moving along one of its paths, for example, thatdefined by the bearings in the saddle 23. Since head Ht is not movinghorizontally, no dog 253 will be employed on means 243. When the switch243 above means 234 engages the dog 253 thereon, said switch willoperate so that current will flow from the generator G through theconductor 213, the normally-closed switch 213 to the conductor 212, thenormally-closed portion of switch 214, the contact members 21I, 213, thebrush 233, binding post 233, conductor 253, switch 243. thence to theground 0' on the frame of the machine, back .to the one side of thesolenoid 219 and finally to the generator G.

Energization of the solenoid 219 will cause the valve 216 to operatesuch that the balls 215, 216 move leftwardly, as viewed in Figure l,whereupon pressure from the source P is adapted to pass the ball 215,enter the conduit 211 and move the piston members 221 leftwardly,thereby to exhaust all of the lines 118, 118, 92, 93, I16, 111, 126 and121. Such action will immediately neutralize all of the operatingelements of the feedworks Th. At the same time, this fluid underpressure will pass through branch 212, valve 213, conduit 214, andeffect the indexing of the drum 116 to its next succeeding position. Itwill be observed, however, that as soon as the drum 116 begins to index,the brush arm 266 moves off the binding post 263, thereby removing theground C from the circuit including the solenoid 219. Accordingly, inorder to effect a complete index of drum 116, it is necessary to providea substitute for ground C' while the arm 266 is moving betweensuccessive binding posts 263. This is accomplished by the normally-openswitch 211 of the compound switch 215.

As previously mentioned, the practical embodiment of the inventionemploys as many as forty or more means 236 that support dogs 253 and anequal number of longitudinally-disposed rows of openings 111 on drum116. Accordingly, forty or more individual switches 252 are required,one for each switch-trip supporting mean; 238; and an equal number ofswitches 249 is also required for the trip-supporting means 229, etc.

Referring to Figure 2, the uprights comprising frame 246 support theswitch-trip supporting means 236 which includes a wire 285 rigidly fixedbetween the uprights of frame 246, and a wire 286 located in a verticalplane spaced from that including wire 285.

The wire 266 is mounted within openings in the uprights of the frame 246in parallel relation to wire 285. The wire 266 is adapted to be axiallymoved for a purpose to be described later. A compression spring 281surrounds the one end of the wire 286 outside of the frame 246. Anadjustable nut 288 is threaded onto the end of rod 286 for varying thecompression of the spring 261. The end of rod 286 opposite thatsupporting spring 281 extends through one upright of the frame 246 andis provided with a micrometer thread 289 and a micrometer nut 296. Byturning the nut 296, the wire 266 may be axially moved in eitherdirection since the spring 261 maintains a constant tension on the wire.

The dog 253 comprises a relatively narrow rectilinear body havingpassages 291 and 292 extending through it for the reception of the wires285 and 286. Look bolts 293 and 294 are threaded into the lower end ofthe dog 253. The bolts 293 and 294 abut against the wire 266. Looseningof bolts 293 and 294 will permit the adjustment of the dog 253 axiallyalong the wires 265 and 266 for approximately locating the dog 253 inits correct position. Tightening of the bolts 293 and 294 will fix thedog 253 to the wire 266. With the dog fixed to the wire 286, accurateadjustment of the dog 253 relatively to the switch 252 may be effectedby turning the micrometer nut 290 on the one end of wire 266. Themicrometer thread 269 of the rod 285 that receives the nut 296 comprises40 threads to the inch so that a complete turn of nut 296 will move dog263 an amount equal to .025 inch. A

10 dial is provided with each nut 296 of ten equal divisions so that itis possible accurately to move dog 253 an amount equal to .0025 inch,and it is possible to estimate movements of dog 253 of less than .061inch.

Figures 2, 3, 4 and 5 show one switch 252 in detail with its attendingparts. Since all switches 249 and 252 are identical, only one will bedescribed in detail. In the present embodiment of the invention, theswitch-supporting members 248 and 251 are moved over their respectiveswitch-trip supporting means and said means remain stationary. Ofcourse, whether the supporting means move or the switch supports move isimmaterial, so' long as relative motion between the two is provided.

The novel circuit includes a series connection between four essentialelements, including: (1) a source of voltage, which in the presentembodiment is about thirty-two volts, and is represented by generator G,Fig. 1; (2) an electrically operated load device which in the presentembodiment is solenoid 219; (3) an electrical contact adapted to beoperated relatively quickly and capable of relatively wide separationwhen open, which comprises arm 266 of distributor 264; and (4) acircuit-energizing contact which, in the present embodiment, is operatedin response to the movement of the tool turret and comprises switch 252.The operation of the circuit including these four essential elementsmust be such that the relatively quick-acting contact is first closedwhich establishes the circuit as far as the circuit-energizing contactor switch 252. When the turret head reaches its destination, switch 252is operated thereby energizing the circuit. Energization of the circuitoperates the solenoid 219 which in turn actuates the quick-actingcontact 266 to de-energize the circuit. Finally, the circuit-energizingcontact (switch 252) is opened only after the quick-acting contact hasbeen opened. The above-described operation of the circuit preventsdetrimental arcing of the circuit-energizing contact (switch 252) whichis the key to the accuracy of the control. Accordingly, the surfaces ofthe movable parts of the contact of switch 252 are never altered bymelting due to detrimental arcing.

The member 251 which supports the switches 252 is composed of insulatingmaterial and is fixed to bracket 256 that is moved between the uprightsof the frame 246 in response to the horizontal movement of head Ht. Ametallic switch-supporting body 295 extending throughout the entirelength of the insulating member 251 is rigidly bolted to it. The member251 is provided with a plurality of holes 296 that extend through themember 251 and are aligned as shown in Figure 3. The metallic body 295is provided with an identical series of holes or bores 291 that areslightly larger in diameter, but axially aligned relatively to the holes296. A plunger 298 is located in each of the holes 291 and includes astem portion 299 that extends upwardly through the hole 296 in theinsulating block 251. A coil spring 366 is located within the holes 291between the block 251 and a shoulder 361 on the plunger 298. The lowerend of the plunger 296 rests on an actuating member 362. The actuatingmember 362 is shown in Figure 5 and comprises a flat plate having anarcuate portion 3113 joined by tangential portions 364, 365 on each sidethereof. The actuator 362 is also provided with trunnions 366, 861 thatextend through and beyond the actuator 362 for equal distances on eachside 01 said actuator. The lower portion of the body 295 is providedwith a series 01 slots 295' each of which extends from the bottom of themember 295 upwardly to the dotted line 888. There is a slot 295' alignedwith each or the holes 281 and plungers 298. The intersection betweeneach 01 the slots 295' and the lower end of its respective hole 291forms a seat below which the lower end of plunger 298 will not move. Atrunnion-receiving portion 398 is provided on each side of the block 295at the lower end of an arcuate surface M9. The one arcuate surface 9i8is slotted at 3H for facilitating the assembly of the actuator 382. Thisassembly is accomplished by locating the trunnion 895 within the slot 3,thereby permitting the trunnion 381 on the opposite end of the arcuator382 to clear the shoulder M2 the body 295 and become seated in itstrunnion-receiving portion 389. Seating of the trunnion 381 adjacent theshoulder 3i2 locates the opposite trunnion 385 beyond the slot 3i i sothat it is urged downwardly to its trunnion-receiving portion 389 by theaction of the spring-pressed plunger 298. As shown in Figure 2, a slightclearance is provided between the trunnions 388, 381 and the arcuatewalls 3iil. This clearance is always taken up, as evidenced in Figure 2by the absence of clearance about trunnion 381, before the switch 252 isoperated by dog 253.

The construction and arrangement of the parts of the switch 252 and itsattending parts are such that a great number of switches 252 can belocated within a minimum of space. The relatively thin, flat plates 302,together with the overall length of the trunnions 98] extending on bothoi its sides, need not exceed the maximum diameter or the plunger 299whereby the only limitation on spacing of switches 252 is the necessarywall thickness between bores 291. In the present embodiment, theplungers 298 are located on 7/32 inch diameters. which gives some ideaof the number of switches 252 that can be located within a given space.

Spring conductors 8i3 are provided alternately on each side of theinsulating member 25i such that their free ends overlie the tops of theholes 298 within which the portions 299 of the plungers 299 are located.Each 01 these free ends oi the conductors contact portion 3i4 directlyover the holes 295. The spring 3i3 resiliently urges this contact firmlyinto engagement with the top of the rigid body member 25i. A slightclearance is provided between the top of the stem portion 299 and thehardened steel contact 3. The fixed end oi each conductor M3 isconnected to one of the wires 254 to 28i that lead to the distributor264.

Each oi the actuators 882 is provided with a depending .portion 3i5 thatextends downwardly to a point where it will engage either side of thedog 253. An abutting engagement between the portion 3i5 and either faceof dog 253 always occurs totally within a surface that is at rightangles to the direction of relative movement between the dog 253 andswitch 252. Accordingly, slight transverse movement of dog 253relatively to the direction of the relative movement between it andswitch 252 does not afiect the point at which contact between 3 and theupper end of stem 299 occurs. Engagement between M and dog 252 in anyother manner will introduce detrimental inaccuracies to the apparatus.Movement of the block l rightwardly as shown in Figure 2 will cause theactuator 882 to pivot about M3 is provided with a hardened steel thetrunnion 981 adjacent shoulder 9i2 causing the arcuate surface 399 toforce the plunger 299 upwardly against the action 01' spring 999. Upwardmovement oi the plunger 299 causes abutting contact to be establishedbetween the contact M4 and the top of the stem 299, thereby groundingthe circuit including the conductor 254 through the ground C.Accordingly, no wiping action between contact 3 and the top of stem 288occurs which, therefore, eliminates all wear between said contacts.Continued movement of the member 25i rightwardly permits the ireepassage oi the unit over the dog 258 without afiecting the operabilityof the switch because spring 3 yields and always returns contact 9 toits initial position in flrm contact against the rigid body 25I. Sincethe construction of the trunnions 888, 381 and the surfaces 8|8 areidentical, movement of the member 25i leitwardly after it has passed thedog 253 causes depending portion 3I5 to engage dog 253 well within thesurface of its righthand side and, therefore. causes an identical action01 the switch 252, as previously described.

As previously stated, switches 252 consume very little space. In orderthat the combined unit including all switches 252 and dogs 253 willoccupy a minimum 01 space, the micrometer adjusting means including thenuts 298 and the resiliently mounted wires 286 alternate in positionwith the fixed wires 285 in adjacent dogs 253. By this means, succeedingsets of wires 295, 288 can be located so close to each other that theirrespective adjusting mechanisms overlap.

There are as many switches 252 including plungers 298 and actuators 382as there are switch-trip supporting means 238 to 245 inclusive; andthere are as many switches 249, identical with switches 252, as thereare switch-trip supporting means 229 to 238 inclusive. All of theseswitches 252 and 249 are identical, as well as each of the switch-tripsupporting means Although the various features oi the improved controlmechanism have been shown and described in detail to fully disclose oneembodiment of the invention, it will be evident that numerous changesmay be made in such details, and certain features can be used withoutothers, without departing from the principles of the invention.

What is claimed is:

1. An electrical circuit for a translatable device, the termination ofthe movements of which is to be repeated with extreme accuracy,comprising in series arrangement, a. source of voltage; an operatingmeans for initiating the movements oi said device and adapted to beenergized by said source of voltage; contact means capable of relativelywide separation and adapted to be opened relatively quickly by theaction of said operating means; other contact means adapted to be closedto energize said circuit; and means movable with said translatabledevice tor closing said other contact means at any desired rate, theconstruction and arrangement of parts being such that said other contactmeans is adapted to be opened only after the operation of said operatingmeans.

2. An electrical circuit tor a translatable device, the termination ofthe movements of which is to be repeated with extreme accuracy,comprising in series arrangement, a source of direct current; anoperating means for initiating the movements or said device and adaptedto be energized by such source of direct current; contact means capableoi. relatively wide separation and adapted to be opened relativelyquickly by the action of said operating means; other contact meansadapted to be closed to energize said circuit; and means movable withsaid translatable device for closing said other contact means at anydesired rate, the construction and arrangement of parts being such thatsaid other contact means is adapted to be opened only after theoperation of said operating means.

3. An electrical circuit for a translatable device, the termination ofthe movements or which is to be repeated with extreme accuracy,comprising in series arrangement, a source voltage; operating means forinitiating the movements of said device and adapted to be energized bysaid source of voltage; a plurality of contact means capable ofrelatively wide separation and adapted successively to be connected intosaid series circuit and to be opened relatively quickly by the action ofsaid operating means; a plurality oi other contact means for energizinsaid circuit, at least one for each of said quick-opening contact means,adapted successively to be connected into said series circuitsimultaneously with its corresponding quick-opening contact means by theaction of said operatin means; and means movable with said translatabledevice for closing said other contact means at any desired rate forenergizing said circuit, the construction and arrangement of the partsbeing such that the opening of the other said contact means which wasclosed to energize said circuit occurs subsequently to the opening ofits corresponding quick-opening contact means.

4. An electrical circuit for a translatable device, the termination ofthe movements of which is to be repeated with extreme accuracy,comprising in series arrangement, a source of direct current; anoperating means having a substantial resist ance for initiating themovements of said device and adapted to be energized by said source ofcurrent; a plurality of contact means capable of relatively wideseparation and adapted successively to be connected into said seriescircuit and to be opened relatively quickly by the action of saidoperatin means; a plurality of other contact means for energizing saidcircuit, at least one for each of said quick-opening contact means,adapted successively to be connected into said series circuitsimultaneously with its corresponding quick-opening contact means by theaction of said operating means; and means movable with said translatabledevice for closing said other contact means at any desired rate forenergizing said circuit, the construction and arrangement of parts beingsuch that the opening of the other said contact means which was closedto energize said circuit occurs subsequently to the opening of itscorresponding quick-opening contact means.

5. An electrical circuit for a translatable device, the termination ofthe movements of which is to be repeated with extremeaccuracy,.comprising in series arrangement, a source of voltage; anoperating means for initiating the movements of said device and adaptedto be energized by said source of voltage; a plurality of contact meanscapable of relatively wide separation and adapted successively to beconnected into said series circuit and to be opened relatively quicklyby the action of said operating means; a plurality of sets of contactmeans each set including a plurality of contacts arranged in parallelrelation relatively to each other, and at least one of said contactsbeing provided for each of said quick-opening contact means, each set ofsaid contact means being adapted successively to be connected into saidseries circuit simultaneously with its corresponding quick-openingcontact means by the action of said operating means; and means movablewith said translatable device ior closing any of said parallel-arrangedcontact means at any desired rate 101' energizing said circuit, theconstruction and arrangement ol' the parts being such that anyparallel-arranged contact tnat has been closed to energize the circuitis opened only alter the opening of its corresponding quick-openingcontact means.

6. An electrical circuit comprising in series atrangement a source ofdirect current; an operating means adapted to be energized by saidsource of direct current; contact means capable of relatively wideseparation and adapted to be opened relatively quickly; other contactmeans adapted to be closed to energize said circuit; and means forclosing said other contact means at any desired rate, the constructionand arrangement of parts being such that said other contact means isadapted to be opened only after the opening of said quick-openingcontact means.

7. An electrical circuit comprising in series arrangement, a source ofvoltage; operating means adapted to be energized by said source ofvoltage; a plurality of contact means capable of relatively wideseparation and adapted successively to be connected into said seriescircuit and to be opened relatively quickly; a plurality 01 othercontact means ior energizing said circuit, at least one tor each of saidquick-opening contact means, adapted successively to be connected intosaid series circuit simultaneously with its corresponding quick-openingcontact means; and means for closing said other contact means at anydesired rate for energizing said circuit, the construction andarrangement 01' the parts being such that the opening of the other saidcontact means which was closed to energize said circuit occurssubsequently to the opening of its corresponding quick-opening contactmeans.

8. An electrical circuit comprising in series arrangement, a source ofdirect current; an operating means adapted to be energized by saidsource of direct current; a plurality of contact means capable ofrelatively wide separation and adapted successively to be connected intosaid series circuit and to be opened relatively quickly; a, plurality ofsets of contact means, each set including a plurality of contactsarranged in parallel relation relatively to each other, and at least oneset of said contacts being provided for each of said quick-openingcontact means, each set of said parallel-arranged contact means beingadapted successively to be connected into said series circuitsimultaneously with its corresponding quick-opening contact means; andmeans for closing any of said parallel-arranged contact means at anydesired rate for energizing said circuit, the construction andarrangement of the parts being such that any parallelarranged contactthat has been closed to energize the circuit is opened only after theopening of its corresponding quick-opening contact means.

9. An electrical circuit comprising in series arrangement, a source ofdirect current; an operating means adapted to be energized by saidsource of direct current; a plurality of contact means capable ofrelatively wide separation and adapted successively to be connected intosaid series circuit and to be opened relatively quickly 15 by the actionof said operating means; a plurality of sets of contact means each setincluding a plurality of contacts arranged in parallel relationrelatively to each other, and at least one set of said contacts beingprovided for each of said quick-opening contact means, each set of saidcontact means being adapted successively to be connected into saidseries circuit simultaneously with its corresponding quick-openingcontact means by the action of said operating means; and means forclosing any of said parallel-arranged contact means at any desired ratefor energizing said circuit, the construction and arrangement of the.parts being such that any parallel-arranged contact that has beenclosed to energize the circuit is opened only after the opening of itscorresponding quick-openin contact means.

10. An electrical circuit comprising in series relation, a source ofvoltage; electrically operated means having a substantial resistance;contact means; means for closing said contact means at any desired ratefor energizing said circuit; and means for tie-energizing said circuitby the operation of said electrically-operated means prior to theopening of said contact means.

11. An electrical circuit comprising in series relation, a source ofvoltage: a plurality of contact means; means for successively connectingand disconnecting said contact means into and from said series circuit;means for closing each of said contact means for energizing said circuitwhen it is connected into said circuit; and means for operating saidconnecting and disconnecting means prior to the opening of the contactmeans that energized said circuit.

12. An electrical circuit comprising in series relation. a source ordirect current; a plurality 18 I 01' contact means; means forsuccessively connecting and disconnecting said contact means into andfrom said series circuit; means for closing each of said contact meansfor energizing said circuit when it is connected into said circuit; andmeans for operating said connecting and disconnecting means prior to theopening of the contact means that energized said circuit.

13. An electrical circuit comprising in series relation, a source ofvoltage; a plurality of sets of contact means, each set comprising aplurality of contact means arranged in parallel relation relatively toeach other; means for successively connecting and disconnecting saidsets of contact means into and from said series circuit; means forclosing each of said contact means for energizing said circuit when itis connected into said circuit; and means for operating said connectingand disconnecting means prior to the opening of the parallel-arrangedcontact means that last energized said circuit.

EDWARD P. BULLARD, III.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 481,785 Cravath Aug. 30, 1892933,211 Van Valkenburg Sept. 7, 1909 1,850,321 Greenwood Mar. 22, 19321,894,458 Altgelt Jan. 17, 1933 2,065,859 Kirk Dec. 29, 1936 2,331,997Mensenkamp Oct. 19. 1943 2,339,839 Curtis Jan. 25, 1944 2,382,078 LongAug. 14, 1945

